Discontinuous reception operation method

ABSTRACT

The present specification proposes a discontinuous reception operation method characterized by: in a wireless communication system, a terminal in which a plurality of cells are configured performing a physical downlink control channel (PDCCH) monitoring on-duration; receiving bandwidth part (BWP) setting information, wherein the BWP setting information informs a specific BWP; receiving a PDCCH on the basis of the PDCCH monitoring, wherein the PDCCH includes dormant indication information for a specific cell from among the plurality of cells of the terminal; and activating the specific BWP on the basis of the dormant indication information indicating non-dormancy.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119(e), this application is a continuation of International Application PCT/KR2020/011690, with an international filing date of Sep. 1, 2020, which claims the benefit of U.S. Provisional Patent Application No. 62/932,604, filed on Nov. 8, 2019, Korean Patent Application No. 10-2019-0129268, filed on Oct. 17, 2019, and Korean Patent Application No. 10-2019-0141053, filed on Nov. 6, 2019, the contents of which are hereby incorporated by reference herein in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to wireless communication.

Related Art

As a growing number of communication devices require higher communication capacity, there is a need for advanced mobile broadband communication as compared to existing radio access technology (RAT). Massive machine-type communication (MTC), which provides a variety of services anytime and anywhere by connecting a plurality of devices and a plurality of objects, is also one major issue to be considered in next-generation communication. In addition, designs for communication systems considering services or user equipments (UEs) sensitive to reliability and latency are under discussion. Introduction of next-generation RAT considering enhanced mobile broadband communication, massive MTC, and ultra-reliable and low-latency communication (URLLC) is under discussion. In the disclosure, for convenience of description, this technology may be referred to as new RAT or new radio (NR).

In the LTE system, a dormant state is defined in order to rapidly perform activation/deactivation of a secondary cell (SCell), and when a specific SCell is set to a dormant state, a UE may not monitor a PDCCH for the cell. Thereafter, in order to rapidly activate the corresponding SCell, it is defined that measurement and reporting are performed in the dormant state to monitor the channel condition and link status of the corresponding cell. For example, when a specific SCell is set to a dormant state, a UE does not perform PDCCH monitoring but may perform measurement and reporting for channel state information (CSI)/radio resource management (RRM). In the NR system, the aforementioned dormant state or a dormancy behavior may be defined in units of BWP.

SUMMARY

The present disclosure provides a discontinuous reception operation method.

Advantageous Effects

According to the present disclosure, a discontinuous reception operation based on BWP activation in consideration of power saving of a UE is provided.

Effects obtained through specific examples of this specification are not limited to the foregoing effects. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand or derive from this specification. Accordingly, specific effects of the disclosure are not limited to those explicitly indicated herein but may include various effects that may be understood or derived from technical features of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a communication system 1 applied to the disclosure.

FIG. 2 illustrates a wireless device that is applicable to the disclosure.

FIG. 3 illustrates a signal processing circuit for a transmission signal.

FIG. 4 illustrates another example of a wireless device applied to the disclosure.

FIG. 5 illustrates a hand-held device applied to the disclosure.

FIG. 6 illustrates a vehicle or an autonomous driving vehicle applied to the disclosure.

FIG. 7 illustrates a vehicle applied to the disclosure.

FIG. 8 illustrates a XR device applied to the disclosure.

FIG. 9 illustrates a robot applied to the disclosure.

FIG. 10 illustrates an AI device applied to the disclosure.

FIG. 11 shows a wireless communication system to which the present disclosure may be applied.

FIG. 12 is a diagram showing a wireless protocol architecture for a user plane.

FIG. 13 is a diagram showing a wireless protocol architecture for a control plane.

FIG. 14 shows another wireless communication system to which the present disclosure may be applied.

FIG. 15 illustrates a functional division between NG-RAN and 5GC.

FIG. 16 illustrates an example of a frame structure that may be applied in NR.

FIG. 17 illustrates a slot structure.

FIG. 18 shows an example of a dormancy behavior.

FIG. 19 shows an example of a BWP operation.

FIG. 20 shows another example of a BWP operation of a UE.

FIG. 21 is a flowchart of an example of a discontinuous reception method of a UE.

FIG. 22 is a flowchart illustrating an example of performing an idle mode DRX operation.

FIG. 23 illustrates an example of an idle mode DRX operation.

FIG. 24 illustrates an example of a DRX cycle.

FIG. 25 is a flowchart of a C-DRX operation.

FIG. 26 illustrates an example of a C-DRX operation.

FIG. 27 illustrates power consumption depending on a state of a UE.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

As used herein, “A or B” may mean “only A”, “only B”, or “both A and B”. That is, “A or B” may be interpreted as “A and/or B” herein. For example, “A, B or C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, and C”.

As used herein, a slash (/) or a comma (,) may mean “and/or”. For example, “A/B” may mean “A and/or B”. Therefore, “A/B” may include “only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B, or C”.

As used herein, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. Further, as used herein, “at least one of A or B” or “at least one of A and/or B” may be interpreted equally as “at least one of A and B”.

As used herein, “at least one of A, B, and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, and C”. Further, “at least one of A, B, or C” or “at least one of A, B, and/or C” may mean “at least one of A, B, and C”.

As used herein, parentheses may mean “for example”. For instance, the expression “control information (PDCCH)” may mean that a PDCCH is proposed as an example of control information. That is, control information is not limited to a PDCCH, but a PDCCH is proposed as an example of control information. Further, the expression “control information (i.e., a PDCCH)” may also mean that a PDCCH is proposed as an example of control information.

Technical features that are separately described in one drawing may be implemented separately or may be implemented simultaneously.

Hereinafter, an example of a communication system to which the disclosure is applied is described.

Various descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein may be applied to, but not limited to, various fields requiring wireless communication/connection (e.g., 5G) between devices.

Hereinafter, specific examples are illustrated with reference to drawings. In the following drawings/description, unless otherwise indicated, like reference numerals may refer to like or corresponding hardware blocks, software blocks, or functional blocks.

FIG. 1 illustrates a communication system 1 applied to the disclosure.

Referring to FIG. 1, the communication system 1 applied to the disclosure includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a radio access technology (e.g., 5G new RAT (NR) or Long-Term Evolution (LTE)) and may be referred to as a communication/wireless/5G device. The wireless device may include, but limited to, a robot 100 a, a vehicle 100 b-1 and 100 b-2, an extended reality (XR) device 100 c, a hand-held device 100 d, a home appliance 100 e, an Internet of things (IoT) device 100 f, and an AI device/server 400. For example, the vehicle may include a vehicle having a wireless communication function, an autonomous driving vehicle, a vehicle capable of inter-vehicle communication, or the like. Here, the vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include augmented reality (AR)/virtual reality (VR)/mixed reality (MR) devices and may be configured as a head-mounted device (HMD), a vehicular head-up display (HUD), a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, or the like. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smart watch or smart glasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, a washing machine, and the like. The IoT device may include a sensor, a smart meter, and the like. The base station and the network may be configured, for example, as wireless devices, and a specific wireless device 200 a may operate as a base station/network node for other wireless devices.

Here, the wireless communication technology implemented in the wireless device of the present disclosure may include a narrowband Internet of Things for low-power communication as well as LTE, NR, and 6G. At this time, for example, NB-IoT technology may be an example of low power wide area network (LPWAN) technology, and may be implemented in standards such as LTE Cat NB1 and/or LTE Cat NB2, may be implemented in the standard of LTE Cat NB1 and/or LTE Cat NB2, and is not limited to the names mentioned above. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present disclosure may perform communication based on LTE-M technology. In this case, as an example, the LTE-M technology may be an example of an LPWAN technology, and may be called by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented by at least any one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M, and is not limited to the names described above. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present disclosure may include at least one of ZigBee, Bluetooth, and LPWAN considering low power communication and is not limited to the names described above. For example, the ZigBee technology may create personal area networks (PAN) related to small/low-power digital communication based on various standards such as IEEE 802.15.4, and may be called by various names.

The wireless devices 100 a to 100 f may be connected to the network 300 through the base station 200. Artificial intelligence (AI) technology may be applied to the wireless devices 100 a to 100 f, and the wireless devices 100 a to 100 f may be connected to an AI server 400 through the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices 100 a to 100 f may communicate with each other via the base station 200/network 300 and may also perform direct communication (e.g. sidelink communication) with each other without passing through the base station/network. For example, the vehicles 100 b-1 and 100 b-2 may perform direct communication (e.g. vehicle-to-vehicle (V2V)/vehicle-to-everything (V2X) communication). Further, the IoT device (e.g., a sensor) may directly communicate with another IoT device (e.g., a sensor) or another wireless device 100 a to 100 f.

Wireless communications/connections 150 a, 150 b, and 150 c may be established between the wireless devices 100 a to 100 f and the base station 200 and between the base stations 200. Here, the wireless communications/connections may be established by various wireless access technologies (e.g., 5G NR), such as uplink/downlink communication 150 a, sidelink communication 150 b (or D2D communication), and inter-base station communication 150 c (e.g., relay or integrated access backhaul (IAB)). The wireless devices and the base station/wireless devices, and the base stations may transmit/receive radio signals to/from each other through the wireless communications/connections 150 a, 150 b, and 150 c. For example, the wireless communications/connections 150 a, 150 b, and 150 c may transmit/receive signals over various physical channels. To this end, at least some of various configuration information setting processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, resource mapping/demapping, and the like), and resource allocation processes may be performed on the basis of various proposals of the disclosure.

FIG. 2 illustrates a wireless device that is applicable to the disclosure.

Referring to FIG. 2, a first wireless device 100 and a second wireless device 200 may transmit and receive radio signals through various radio access technologies (e.g., LTE and NR). Here, the first wireless device 100 and the second wireless device 200 may respectively correspond to a wireless device 100 x and the base station 200 of FIG. 1 and/or may respectively correspond to a wireless device 100 x and a wireless device 100 x of FIG. 1.

The first wireless device 100 includes at least one processor 102 and at least one memory 104 and may further include at least one transceiver 106 and/or at least one antenna 108. The processor 102 may be configured to control the memory 104 and/or the transceiver 106 and to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. For example, the processor 102 may process information in the memory 104 to generate first information/signal and may then transmit a radio signal including the first information/signal through the transceiver 106. In addition, the processor 102 may receive a radio signal including second information/signal through the transceiver 106 and may store information obtained from signal processing of the second information/signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various pieces of information related to the operation of the processor 102. For example, the memory 104 may store a software code including instructions to perform some or all of processes controlled by the processor 102 or to perform the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. Here, the processor 102 and the memory 104 may be part of a communication modem/circuit/chip designed to implement a radio communication technology (e.g., LTE or NR). The transceiver 106 may be connected with the processor 102 and may transmit and/or receive a radio signal via the at least one antennas 108. The transceiver 106 may include a transmitter and/or a receiver. The transceiver 106 may be replaced with a radio frequency (RF) unit. In the disclosure, the wireless device may refer to a communication modem/circuit/chip.

The second wireless device 200 includes at least one processor 202 and at least one memory 204 and may further include at least one transceiver 206 and/or at least one antenna 208. The processor 202 may be configured to control the memory 204 and/or the transceiver 206 and to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. For example, the processor 202 may process information in the memory 204 to generate third information/signal and may then transmit a radio signal including the third information/signal through the transceiver 206. In addition, the processor 202 may receive a radio signal including fourth information/signal through the transceiver 206 and may store information obtained from signal processing of the fourth information/signal in the memory 204. The memory 204 may be connected to the processor 202 and may store various pieces of information related to the operation of the processor 202. For example, the memory 204 may store a software code including instructions to perform some or all of processes controlled by the processor 202 or to perform the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. Here, the processor 202 and the memory 204 may be part of a communication modem/circuit/chip designed to implement a radio communication technology (e.g., LTE or NR). The transceiver 206 may be connected with the processor 202 and may transmit and/or receive a radio signal via the at least one antennas 208. The transceiver 206 may include a transmitter and/or a receiver. The transceiver 206 may be replaced with an RF unit. In the disclosure, the wireless device may refer to a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 are described in detail. At least one protocol layer may be implemented, but limited to, by the at least one processor 102 and 202. For example, the at least one processor 102 and 202 may implement at least one layer (e.g., a functional layer, such as PHY, MAC, RLC, PDCP, RRC, and SDAP layers). The at least one processor 102 and 202 may generate at least one protocol data unit (PDU) and/or at least one service data unit (SDU) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. The at least one processor 102 and 202 may generate a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein. The at least one processor 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, an SDU, a message, control information, data, or information according to the functions, procedures, proposals, and/or methods disclosed herein and may provide the signal to the at least one transceiver 106 and 206. The at least one processor 102 and 202 may receive a signal (e.g., a baseband signal) from the at least one transceiver 106 and 206 and may obtain a PDU, an SDU, a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein.

The at least one processor 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The at least one processor 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, at least one application-specific integrated circuit (ASIC), at least one digital signal processor (DSP), at least one digital signal processing devices (DSPD), at least one programmable logic devices (PLD), or at least one field programmable gate array (FPGA) may be included in the at least one processor 102 and 202. The descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein may be implemented using firmware or software, and the firmware or software may be configured to include modules, procedures, functions, and the like. The firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein may be included in the at least one processor 102 and 202 or may be stored in the at least one memory 104 and 204 and may be executed by the at least one processor 102 and 202. The descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein may be implemented in the form of a code, an instruction, and/or a set of instructions using firmware or software.

The at least one memory 104 and 204 may be connected to the at least one processor 102 and 202 and may store various forms of data, signals, messages, information, programs, codes, indications, and/or commands. The at least one memory 104 and 204 may be configured as a ROM, a RAM, an EPROM, a flash memory, a hard drive, a register, a cache memory, a computer-readable storage medium, and/or a combinations thereof. The at least one memory 104 and 204 may be disposed inside and/or outside the at least one processor 102 and 202. In addition, the at least one memory 104 and 204 may be connected to the at least one processor 102 and 202 through various techniques, such as a wired or wireless connection.

The at least one transceiver 106 and 206 may transmit user data, control information, a radio signal/channel, or the like mentioned in the methods and/or operational flowcharts disclosed herein to at least different device. The at least one transceiver 106 and 206 may receive user data, control information, a radio signal/channel, or the like mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein from at least one different device. For example, the at least one transceiver 106 and 206 may be connected to the at least one processor 102 and 202 and may transmit and receive a radio signal. For example, the at least one processor 102 and 202 may control the at least one transceiver 106 and 206 to transmit user data, control information, or a radio signal to at least one different device. In addition, the at least one processor 102 and 202 may control the at least one transceiver 106 and 206 to receive user data, control information, or a radio signal from at least one different device. The at least one transceiver 106 and 206 may be connected to the at least one antenna 108 and 208 and may be configured to transmit or receive user data, control information, a radio signal/channel, or the like mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein through the at least one antenna 108 and 208. In this document, the at least one antenna may be a plurality of physical antennas or may be a plurality of logical antennas (e.g., antenna ports). The at least one transceiver 106 and 206 may convert a received radio signal/channel from an RF band signal into a baseband signal in order to process received user data, control information, a radio signal/channel, or the like using the at least one processor 102 and 202. The at least one transceiver 106 and 206 may convert user data, control information, a radio signal/channel, or the like, processed using the at least one processor 102 and 202, from a baseband signal to an RF bad signal. To this end, the at least one transceiver 106 and 206 may include an (analog) oscillator and/or a filter.

FIG. 3 illustrates a signal processing circuit for a transmission signal.

Referring to FIG. 3, the signal processing circuit 1000 may include a scrambler 1010, a modulator 1020, a layer mapper 1030, a precoder 1040, a resource mapper 1050, and a signal generator 1060. Operations/functions illustrated with reference to FIG. 3 may be performed, but not limited to, in the processor 102 and 202 and/or the transceiver 106 and 206 of FIG. 2. Hardware elements illustrated in FIG. 3 may be configured in the processor 102 and 202 and/or the transceiver 106 and 206 of FIG. 2. For example, blocks 1010 to 1060 may be configured in the processor 102 and 202 of FIG. 2. Alternatively, blocks 1010 to 1050 may be configured in the processor 102 and 202 of FIG. 2, and a block 1060 may be configured in the transceiver 106 and 206 of FIG. 2.

A codeword may be converted into a radio signal via the signal processing circuit 1000 of FIG. 3. Here, the codeword is an encoded bit sequence of an information block. The information block may include a transport block (e.g., a UL-SCH transport block and a DL-SCH transport block). The radio signal may be transmitted through various physical channels (e.g., a PUSCH or a PDSCH).

Specifically, the codeword may be converted into a scrambled bit sequence by the scrambler 1010. A scrambled sequence used for scrambling is generated on the basis of an initialization value, and the initialization value may include ID information about a wireless device. The scrambled bit sequence may be modulated into a modulation symbol sequence by the modulator 1020. A modulation scheme may include pi/2-binary phase shift keying (pi/2-BPSK), m-phase shift keying (m-PSK), m-quadrature amplitude modulation (m-QAM), and the like. A complex modulation symbol sequence may be mapped to at least one transport layer by the layer mapper 1030. Modulation symbols of each transport layer may be mapped to a corresponding antenna port(s) by the precoder 1040 (precoding). Output z from the precoder 1040 may be obtained by multiplying output y from the layer mapper 1030 by a precoding matrix W of N*M, where N is the number of antenna ports, and M is the number of transport layers. Here, the precoder 1040 may perform precoding after performing transform precoding (e.g., DFT transform) on complex modulation symbols. Alternatively, the precoder 1040 may perform precoding without performing transform precoding.

The resource mapper 1050 may map a modulation symbol of each antenna port to a time-frequency resource. The time-frequency resource may include a plurality of symbols (e.g., CP-OFDMA symbols or DFT-s-OFDMA symbols) in the time domain and may include a plurality of subcarriers in the frequency domain. The signal generator 1060 may generate a radio signal from mapped modulation symbols, and the generated radio signal may be transmitted to another device through each antenna. To this end, the signal generator 1060 may include an inverse fast Fourier transform (IFFT) module, a cyclic prefix (CP) inserter, a digital-to-analog converter (DAC), a frequency upconverter, and the like.

A signal processing procedure for a received signal in a wireless device may be performed in the reverse order of the signal processing procedure 1010 to 1060 of FIG. 3. For example, a wireless device (e.g., 100 and 200 of FIG. 2) may receive a radio signal from the outside through an antenna port/transceiver. The received radio signal may be converted into a baseband signal through a signal reconstructor. To this end, the signal reconstructor may include a frequency downconverter, an analog-to-digital converter (ADC), a CP remover, and a fast Fourier transform (FFT) module. The baseband signal may be reconstructed to a codeword through resource demapping, postcoding, demodulation, and descrambling. The codeword may be reconstructed to an original information block through decoding. Thus, a signal processing circuit (not shown) for a received signal may include a signal reconstructor, a resource demapper, a postcoder, a demodulator, a descrambler and a decoder.

FIG. 4 illustrates another example of a wireless device applied to the disclosure. The wireless device may be configured in various forms depending on usage/service.

Referring to FIG. 4, the wireless devices 100 and 200 may correspond to the wireless device 100 and 200 of FIG. 2 and may include various elements, components, units, and/or modules. For example, the wireless device 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit may include a communication circuit 112 and a transceiver(s) 114. For example, the communication circuit 112 may include the at least one processor 102 and 202 and/or the at least one memory 104 and 204 of FIG. 2. For example, the transceiver(s) 114 may include the at least one transceiver 106 and 206 and/or the at least one antenna 108 and 208 of FIG. 2. The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional components 140 and controls overall operations of the wireless device. For example, the control unit 120 may control electrical/mechanical operations of the wireless device on the basis of a program/code/command/information stored in the memory unit 130. In addition, the control unit 120 may transmit information stored in the memory unit 130 to the outside (e.g., a different communication device) through a wireless/wired interface via the communication unit 110 or may store, in the memory unit 130, information received from the outside (e.g., a different communication device) through the wireless/wired interface via the communication unit 110.

The additional components 140 may be configured variously depending on the type of the wireless device. For example, the additional components 140 may include at least one of a power unit/battery, an input/output (I/O) unit, a driving unit, and a computing unit. The wireless device may be configured, but not limited to, as a robot (100 a in FIG. 1), a vehicle (100 b-1 or 100 b-2 in FIG. 1), an XR device (100 c in FIG. 1), a hand-held device (100 d in FIG. 1), a home appliance (100 e in FIG. 1), an IoT device (100 f in FIG. 1), a terminal for digital broadcasting, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or financial device), a security device, a climate/environmental device, an AI server/device (400 in FIG. 1), a base station (200 in FIG. 1), a network node, or the like. The wireless device may be mobile or may be used in a fixed place depending on usage/service.

In FIG. 4, all of the various elements, components, units, and/or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface, or at least some thereof may be wirelessly connected through the communication unit 110. For example, the control unit 120 and the communication unit 110 may be connected via a cable in the wireless device 100 and 200, and the control unit 120 and a first unit (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. In addition, each element, component, unit, and/or module in wireless device 100 and 200 may further include at least one element. For example, the control unit 120 may include at least one processor set. For example, the control unit 120 may be configured as a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, and the like. In another example, the memory unit 130 may include a random-access memory (RAM), a dynamic RAM (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory, and/or a combination thereof.

Next, an illustrative configuration of FIG. 4 is described in detail with reference to the accompanying drawing.

FIG. 5 illustrates a hand-held device applied to the disclosure. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smart watch or smart glasses), and a portable computer (e.g., a notebook). The hand-held device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

Referring to FIG. 5, the hand-held device 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a memory unit 130, a power supply unit 140 a, an interface unit 140 b, and an input/output unit 140 c. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110 to 130/140 a to 140 c correspond to the blocks 110 to 130/140 in FIG. 4, respectively.

The communication unit 110 may transmit and receive a signal (e.g., data, a control signal, or the like) to and from other wireless devices and base stations. The control unit 120 may control various components of the hand-held device 100 to perform various operations. The control unit 120 may include an application processor (AP). The memory unit 130 may store data/parameter/program/code/command necessary to drive the hand-held device 100. Further, the memory unit 130 may store input/output data/information. The power supply unit 140 a supplies power to the hand-held device 100 and may include a wired/wireless charging circuit, a battery, and the like. The interface unit 140 b may support a connection between the hand-held device 100 and a different external device. The interface unit 140 b may include various ports (e.g., an audio input/output port and a video input/output port) for connection to an external device. The input/output unit 140 c may receive or output image information/signal, audio information/signal, data, and/or information input from a user. The input/output unit 140 c may include a camera, a microphone, a user input unit, a display unit 140 d, a speaker, and/or a haptic module.

For example, in data communication, the input/output unit 140 c may obtain information/signal (e.g., a touch, text, voice, an image, and a video) input from the user, and the obtained information/signal may be stored in the memory unit 130. The communication unit 110 may convert information/signal stored in the memory unit into a radio signal and may transmit the converted radio signal directly to a different wireless device or to a base station. In addition, the communication unit 110 may receive a radio signal from a different wireless device or the base station and may reconstruct the received radio signal to original information/signal. The reconstructed information/signal may be stored in the memory unit 130 and may then be output in various forms (e.g., text, voice, an image, a video, and a haptic form) through the input/output unit 140 c.

FIG. 6 illustrates a vehicle or an autonomous driving vehicle applied to the disclosure. The vehicle or the autonomous driving may be configured as a mobile robot, a car, a train, a manned/unmanned aerial vehicle (AV), a ship, or the like.

Referring to FIG. 6, the vehicle or the autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, and an autonomous driving unit 140 d. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110/130/140 a to 140 d correspond to the blocks 110/130/140 in FIG. 4, respectively.

The communication unit 110 may transmit and receive a signal (e.g., data, a control signal, or the like) to and from external devices, such as a different vehicle, a base station (e.g. a base station, a road-side unit, or the like), and a server. The control unit 120 may control elements of the vehicle or the autonomous driving vehicle 100 to perform various operations. The control unit 120 may include an electronic control unit (ECU). The driving unit 140 a may enable the vehicle or the autonomous driving vehicle 100 to run on the ground. The driving unit 140 a may include an engine, a motor, a power train, wheels, a brake, a steering device, and the like. The power supply unit 140 b supplies power to the vehicle or the autonomous driving vehicle 100 and may include a wired/wireless charging circuit, a battery, and the like. The sensor unit 140 c may obtain a vehicle condition, environmental information, user information, and the like. The sensor unit 140 c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight sensor, a heading sensor, a position module, vehicular forward/backward vision sensors, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, and the like. The autonomous driving unit 140 d may implement a technology for maintaining a driving lane, a technology for automatically adjusting speed, such as adaptive cruise control, a technology for automatic driving along a set route, a technology for automatically setting a route and driving when a destination is set, and the like.

For example, the communication unit 110 may receive map data, traffic condition data, and the like from an external server. The autonomous driving unit 140 d may generate an autonomous driving route and a driving plan on the basis of obtained data. The control unit 120 may control the driving unit 140 a to move the vehicle or the autonomous driving vehicle 100 along the autonomous driving route according to the driving plan (e.g., speed/direction control). During autonomous driving, the communication unit 110 may aperiodically/periodically obtain updated traffic condition data from the external server and may obtain surrounding traffic condition data from a neighboring vehicle. Further, during autonomous driving, the sensor unit 140 c may obtain a vehicle condition and environmental information. The autonomous driving unit 140 d may update the autonomous driving route and the driving plan on the basis of newly obtained data/information. The communication unit 110 may transmit information about a vehicle location, an autonomous driving route, a driving plan, and the like to the external server. The external server may predict traffic condition data in advance using AI technology or the like on the basis of information collected from vehicles or autonomous driving vehicles and may provide the predicted traffic condition data to the vehicles or the autonomous driving vehicles.

FIG. 7 illustrates a vehicle applied to the disclosure. The vehicle may be implemented as a means of transportation, a train, an air vehicle, a ship, and the like.

Referring to FIG. 7, the vehicle 100 may include a communication unit 110, a control unit 120, a memory unit 130, an input/output unit 140 a, and a positioning unit 140 b. Herein, blocks 110 to 130/140 a to 140 b correspond to block 110 to 130/140 of FIG. 4, respectively.

The communication unit 110 may transmit/receive signals (e.g., data, control signals, etc.) with other vehicles or external devices such as a base station. The control unit 120 may control components of the vehicle 100 to perform various operations. The memory unit 130 may store data/parameters/programs/codes/commands supporting various functions of the vehicle 100. The input/output unit 140 a may output an AR/VR object based on information in the memory unit 130. The input/output unit 140 a may include a HUD. The positioning unit 140 b may acquire position information of the vehicle 100. The location information may include absolute location information of the vehicle 100, location information within a driving line, acceleration information, location information with a neighboring vehicle, and the like. The positioning unit 140 b may include a GPS and various sensors.

For example, the communication unit 110 of the vehicle 100 may receive map information, traffic information, and the like from an external server and store it in the memory unit 130. The positioning unit 140 b may obtain vehicle position information through GPS and various sensors and store it in the memory unit 130. The control unit 120 may generate a virtual object based on map information, traffic information, vehicle location information, and the like, and the input/output unit 140 a may display the generated virtual object on a window inside the vehicle (1410 and 1420). In addition, the control unit 120 may determine whether the vehicle 100 is normally operating within the driving line based on the vehicle location information. When the vehicle 100 abnormally deviates from the driving line, the control unit 120 may display a warning on the windshield of the vehicle through the input/output unit 140 a. Also, the control unit 120 may broadcast a warning message regarding the driving abnormality to surrounding vehicles through the communication unit 110. Depending on the situation, the control unit 120 may transmit the location information of the vehicle and information on driving/vehicle abnormality to the related organization through the communication unit 110.

FIG. 8 illustrates a XR device applied to the disclosure. The XR device may be implemented as an HMD, a head-up display (HUD) provided in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like.

Referring to FIG. 8, the XR device 100 a may include a communication unit 110, a control unit 120, a memory unit 130, an input/output unit 140 a, a sensor unit 140 b and a power supply unit 140 c. Herein, blocks 110 to 130/140 a to 140 c correspond to blocks 110 to 130/140 in FIG. 4.

The communication unit 110 may transmit/receive signals (e.g., media data, control signals, etc.) to/from external devices such as other wireless devices, portable devices, or media servers. Media data may include images, images, sounds, and the like. The control unit 120 may control the components of the XR device 100 a to perform various operations. For example, the control unit 120 may be configured to control and/or perform procedures such as video/image acquisition, (video/image) encoding, and metadata generation and processing. The memory unit 130 may store data/parameters/programs/codes/commands necessary for driving the XR device 100 a/creating an XR object. The input/output unit 140 a may obtain control information, data, and the like from the outside, and may output the generated XR object. The input/output unit 140 a may include a camera, a microphone, a user input unit, a display unit, a speaker, and/or a haptic module. The sensor unit 140 b may obtain an XR device state, surrounding environment information, user information, and the like. The sensor unit 140 b may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, a RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, an optical sensor, a microphone, and/or a radar. The power supply unit 140 c supplies power to the XR device 100 a, and may include a wired/wireless charging circuit, a battery, and the like.

For example, the memory unit 130 of the XR device 100 a may include information (e.g., data, etc.) necessary for generating an XR object (e.g., AR/VR/MR object). The input/output unit 140 a may obtain a command to operate the XR device 100 a from the user, and the control unit 120 may drive the XR device 100 a according to the user's driving command. For example, when the user wants to watch a movie or news through the XR device 100 a, the control unit 120 transmits the content request information through the communication unit 130 to another device (e.g., the mobile device 100 b) or can be sent to the media server. The communication unit 130 may download/stream contents such as movies and news from another device (e.g., the portable device 100 b) or a media server to the memory unit 130. The control unit 120 controls and/or performs procedures such as video/image acquisition, (video/image) encoding, and metadata generation/processing for the content, and is acquired through the input/output unit 140 a/the sensor unit 140 b An XR object can be generated/output based on information about one surrounding space or a real object.

Also, the XR device 100 a is wirelessly connected to the portable device 100 b through the communication unit 110, and the operation of the XR device 100 a may be controlled by the portable device 100 b. For example, the portable device 100 b may operate as a controller for the XR device 100 a. To this end, the XR device 100 a may obtain 3D location information of the portable device 100 b, and then generate and output an XR object corresponding to the portable device 100 b.

FIG. 9 illustrates a robot applied to the disclosure. The robot may be classified into industrial, medical, home, military, and the like depending on the purpose or field of use.

Referring to FIG. 9, the robot 100 may include a communication unit 110, a control unit 120, a memory unit 130, an input/output unit 140 a, a sensor unit 140 b, and a driving unit 140 c. Herein, blocks 110 to 130/140 a to 140 c correspond to blocks 110 to 130/140 in FIG. 4.

The communication unit 110 may transmit/receive signals (e.g., driving information, control signal, etc.) to/from external device such as other wireless device, other robot, or a control server. The control unit 120 may perform various operations by controlling the components of the robot 100. The memory unit 130 may store data/parameters/programs/codes/commands supporting various functions of the robot 100. The input/output unit 140 a may obtain information from the outside of the robot 100 and may output information to the outside of the robot 100. The input/output unit 140 a may include a camera, a microphone, an user input unit, a display unit, a speaker, and/or a haptic module, etc. The sensor unit 140 b may obtain internal information, surrounding environment information, user information and the like of the robot 100. The sensor unit may include a proximity sensor, an illumination sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, an optical sensor, a microphone, a radar, and the like. The driving unit 140 c may perform various physical operations such as moving a robot joint. In addition, the driving unit 140 c may make the robot 100 travel on the ground or fly in the air. The driving unit 140 c may include an actuator, a motor, a wheel, a brake, a propeller, and the like.

FIG. 10 illustrates an AI device applied to the disclosure. The AI device may be implemented as a stationary device or a mobile device, such as a TV, a projector, a smartphone, a PC, a laptop, a digital broadcasting terminal, a tablet PC, a wearable device, a set-top box, a radio, a washing machine, a refrigerator, digital signage, a robot, and a vehicle.

Referring to FIG. 10, the AI device 100 may include a communication unit 110, a control unit 120, a memory unit 130, an input unit 140 a, an output unit 140 b, a learning processor unit 140 c, and a sensor unit 140 d. Blocks 110 to 130/140 a to 140 d correspond to the blocks 110 to 130/140 of FIG. 4, respectively.

The communication unit 110 may transmit and receive wired or wireless signals (e.g., sensor information, a user input, a learning mode, a control signal, or the like) to and from external devices, a different AI device (e.g., 100 x, 200, or 400 in FIG. 1) or an AI server (e.g., 400 in FIG. 1) using wired or wireless communication technologies. To this end, the communication unit 110 may transmit information in the memory unit 130 to an external device or may transmit a signal received from the external device to the memory unit 130.

The control unit 120 may determine at least one executable operation of the AI device 100 on the basis of information determined or generated using a data analysis algorithm or a machine-learning algorithm. The control unit 120 may control components of the AI device 100 to perform the determined operation. For example, the control unit 120 may request, retrieve, receive, or utilize data of the learning processor unit 140 c or the memory unit 130 and may control components of the AI device 100 to perform a predicted operation or an operation determined to be preferable among the at least one executable operation. The control unit 120 may collect history information including details about an operation of the AI device 100 or a user's feedback on the operation and may store the history information in the memory unit 130 or the learning processor unit 140 c or may transmit the history information to an external device, such as the AI server (400 in FIG. 1). The collected history information may be used to update a learning model.

The memory unit 130 may store data for supporting various functions of the AI device 100. For example, the memory unit 130 may store data obtained from the input unit 140 a, data obtained from the communication unit 110, output data from the learning processor unit 140 c, and data obtained from the sensing unit 140. Further, the memory unit 130 may store control information and/or a software code necessary for the operation/execution of the control unit 120.

The input unit 140 a may obtain various types of data from the outside of the AI device 100. For example, the input unit 140 a may obtain learning data for model learning and input data to which a learning model is applied. The input unit 140 a may include a camera, a microphone, and/or a user input unit. The output unit 140 b may generate visual, auditory, or tactile output. The output unit 140 b may include a display unit, a speaker, and/or a haptic module. The sensing unit 140 may obtain at least one of internal information about the AI device 100, environmental information about the AI device 100, and user information using various sensors. The sensing unit 140 may include a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint sensor, an ultrasonic sensor, an optical sensor, a microphone, and/or a radar.

The learning processor unit 140 c may train a model including artificial neural networks using learning data. The learning processor unit 140 c may perform AI processing together with a learning processor unit of an AI server (400 in FIG. 1). The learning processor unit 140 c may process information received from an external device through the communication unit 110 and/or information stored in the memory unit 130. In addition, an output value from the learning processor unit 140 c may be transmitted to an external device through the communication unit 110 and/or may be stored in the memory unit 130.

FIG. 11 shows a wireless communication system to which the present disclosure may be applied. The wireless communication system may be referred to as an Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN) or a Long Term Evolution (LTE)/LTE-A system.

The E-UTRAN includes at least one base station (BS) 20 which provides a control plane and a user plane to a user equipment (UE) 10. The UE 10 may be fixed or mobile, and may be referred to as another terminology, such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT), a wireless device, etc. The BS 20 is generally a fixed station that communicates with the UE 10 and may be referred to as another terminology, such as an evolved node-B (eNB), a base transceiver system (BTS), an access point, etc.

The BSs 20 are interconnected by means of an X2 interface. The BSs 20 are also connected by means of an S1 interface to an evolved packet core (EPC) 30, more specifically, to a mobility management entity (MME) through S1-MME and to a serving gateway (S-GW) through S1-U.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway (P-GW). The MME has access information of the UE or capability information of the UE, and such information is generally used for mobility management of the UE. The S-GW is a gateway having an E-UTRAN as an end point. The P-GW is a gateway having a PDN as an end point.

Layers of a radio interface protocol between the UE and the network can be classified into a first layer (L1), a second layer (L2), and a third layer (L3) based on the lower three layers of the open system interconnection (OSI) model that is well-known in the communication system. Among them, a physical (PHY) layer belonging to the first layer provides an information transfer service by using a physical channel, and a radio resource control (RRC) layer belonging to the third layer serves to control a radio resource between the UE and the network. For this, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 12 is a diagram showing a wireless protocol architecture for a user plane. FIG. 13 is a diagram showing a wireless protocol architecture for a control plane. The user plane is a protocol stack for user data transmission. The control plane is a protocol stack for control signal transmission.

Referring to FIGS. 12 and 13, a PHY layer provides an upper layer with an information transfer service through a physical channel. The PHY layer is connected to a medium access control (MAC) layer which is an upper layer of the PHY layer through a transport channel. Data is transferred between the MAC layer and the PHY layer through the transport channel. The transport channel is classified according to how and with what characteristics data is transferred through a radio interface.

Data is moved between different PHY layers, that is, the PHY layers of a transmitter and a receiver, through a physical channel. The physical channel may be modulated according to an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and use the time and frequency as radio resources.

The functions of the MAC layer include mapping between a logical channel and a transport channel and multiplexing and demultiplexing to a transport block that is provided through a physical channel on the transport channel of a MAC Service Data Unit (SDU) that belongs to a logical channel. The MAC layer provides service to a Radio Link Control (RLC) layer through the logical channel.

The functions of the RLC layer include the concatenation, segmentation, and reassembly of an RLC SDU. In order to guarantee various types of Quality of Service (QoS) required by a Radio Bearer (RB), the RLC layer provides three types of operation mode: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through an Automatic Repeat Request (ARQ).

The RRC layer is defined only on the control plane. The RRC layer is related to the configuration, reconfiguration, and release of radio bearers, and is responsible for control of logical channels, transport channels, and PHY channels. An RB means a logical route that is provided by the first layer (PHY layer) and the second layers (MAC layer, the RLC layer, and the PDCP layer) in order to transfer data between UE and a network.

The function of a Packet Data Convergence Protocol (PDCP) layer on the user plane includes the transfer of user data and header compression and ciphering. The function of the PDCP layer on the user plane further includes the transfer and encryption/integrity protection of control plane data.

What an RB is configured means a process of defining the characteristics of a wireless protocol layer and channels in order to provide specific service and configuring each detailed parameter and operating method. An RB can be divided into two types of a Signaling RB (SRB) and a Data RB (DRB). The SRB is used as a passage through which an RRC message is transmitted on the control plane, and the DRB is used as a passage through which user data is transmitted on the user plane.

If RRC connection is established between the RRC layer of UE and the RRC layer of an E-UTRAN, the UE is in the RRC connected state. If not, the UE is in the RRC idle state.

A downlink transport channel through which data is transmitted from a network to UE includes a broadcast channel (BCH) through which system information is transmitted and a downlink shared channel (SCH) through which user traffic or control messages are transmitted. Traffic or a control message for downlink multicast or broadcast service may be transmitted through the downlink SCH, or may be transmitted through an additional downlink multicast channel (MCH). Meanwhile, an uplink transport channel through which data is transmitted from UE to a network includes a random access channel (RACH) through which an initial control message is transmitted and an uplink shared channel (SCH) through which user traffic or control messages are transmitted.

Logical channels that are placed over the transport channel and that are mapped to the transport channel include a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a multicast traffic channel (MTCH).

The physical channel includes several OFDM symbols in the time domain and several subcarriers in the frequency domain. One subframe includes a plurality of OFDM symbols in the time domain. An RB is a resources allocation unit, and includes a plurality of OFDM symbols and a plurality of subcarriers. Furthermore, each subframe may use specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) of the corresponding subframe for a physical downlink control channel (PDCCH), that is, an L1/L2 control channel. A Transmission Time Interval (TTI) is a unit time for transmission, e.g., a subframe or a slot.

Hereinafter, a new radio access technology (new RAT, NR) will be described.

As more and more communication devices require more communication capacity, there is a need for improved mobile broadband communication over existing radio access technology. Also, massive machine type communications (MTC), which provides various services by connecting many devices and objects, is one of the major issues to be considered in the next generation communication. In addition, communication system design considering reliability/latency sensitive service/UE is being discussed. The introduction of next generation radio access technology considering enhanced mobile broadband communication (eMBB), massive MTC (mMTC), ultrareliable and low latency communication (URLLC) is discussed. This new technology may be called new radio access technology (new RAT or NR) in the present disclosure for convenience.

FIG. 14 shows another wireless communication system to which the present disclosure may be applied.

Specifically, FIG. 14 shows a system architecture based on a 5G new radio access technology (NR) system. An entity used in the 5G NR system (hereinafter, simply referred to as “NR”) may absorb some or all functions of the entity (e.g., eNB, MME, S-GW) introduced in FIG. 1 (e.g., eNB, MME, S-GW). The entity used in the NR system may be identified in the name of “NG” to distinguish it from LTE.

Referring to FIG. 14, a wireless communication system includes one or more UEs 11, a next-generation RAN (NG-RAN), and a 5th generation core network (5GC). The NG-RAN consists of at least one NG-RAN node. The NG-RAN node is an entity corresponding to the BS 20 of FIG. 11. The NG-RAN node consists of at least one gNB 21 and/or at least one ng-eNB 22. The gNB 21 provides NR user plane and control plane protocol terminations towards the UE 11. The Ng-eNB 22 provides an E-UTRA user plane and control plane protocol terminations towards the UE 11.

The 5GC includes an access and mobility management function (AMF), a user plane function (UPF), and a session management function (SMF). The AMF hosts functions, such as non-access stratum (NAS) security, idle state mobility processing, and so on. The AMF is an entity including the conventional MMF function. The UPF hosts functions, such as mobility anchoring, protocol data unit (PDU) processing, and so on. The UPF is an entity including the conventional S-GW function. The SMF hosts functions, such as UE Internet Protocol (IP) address allocation, PDU session control, and so on.

The gNB and the ng-eNB are interconnected through an Xn interface. The gNB and the ng-eNB are also connected to the 5GC through an NG interface. More specifically, the gNB and the ng-eNB are connected to the AMF through an NG-C interface, and are connected to the UPF through an NG-U interface.

FIG. 15 illustrates a functional division between an NG-RAN and a 5GC.

Referring to FIG. 15, the gNB may provide functions such as an inter-cell radio resource management (Inter Cell RRM), radio bearer management (RB control), connection mobility control, radio admission control, measurement configuration & provision, dynamic resource allocation, and the like. The AMF may provide functions such as NAS security, idle state mobility handling, and so on. The UPF may provide functions such as mobility anchoring, PDU processing, and the like. The SMF may provide functions such as UE IP address assignment, PDU session control, and so on.

FIG. 16 illustrates an example of a frame structure that may be applied in NR.

Referring to FIG. 16, a frame may be composed of 10 milliseconds (ms) and include 10 subframes each composed of 1 ms.

In the NR, uplink and downlink transmissions may be configured on a frame basis. A radio frame has a length of 10 ms, and may be defined as two 5 ms half-frames (HFs). The HF may be defined as five 1 ms sub-frames (SFs). The SF is divided into one or more slots, and the number of slots in the SF depends on a subcarrier spacing (SCS). Each slot includes 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP). When a normal CP is used, each slot includes 14 symbols. When an extended CP is used, each slot includes 12 symbols. Herein, the symbol may include an OFDM symbol (or CP-OFDM symbol) and an SC-FDMA symbol (or DFT-S-OFDM symbol).

One or a plurality of slots may be included in a subframe according to subcarrier spacings.

The following table 1 illustrates a subcarrier spacing configuration

TABLE 1 μ Δf = 2^(μ) · 15[kHz] Cyclic prefix 0 15 Normal 1 30 Normal 2 60 Normal Extended 3 120 Normal 4 240 Normal

The following table 2 illustrates the number of slots in a frame (N^(frame,μ) _(slot)), the number of slots in a subframe (N^(subframe,μ) _(slot)), the number of symbols in a slot (N^(slot) _(symb)), and the like, according to subcarrier spacing configurations

TABLE 2 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ) 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

Table 3 below illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS, in case of using an extended CP.

TABLE 3 SCS(15*2{circumflex over ( )}μ) N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot) 60 KHz (μ = 2) 12 40 4

NR supports multiple numbers (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, a wide region in the legacy cellular band is supported; and when the SCS is 30 kHz/60 kHz, dense urban areas, low time delay and wide carrier bandwidth are supported; and when the SCS is 60 kHz or more, a bandwidth of more than 24.25 GHz is supported in order to overcome phase noise.

The NR frequency band may be defined as two types of frequency ranges (FR1 and FR2). A numerical value of the frequency range may be changed and, for example, the two types of frequency ranges (FR1 and FR2) may be as shown in Table 4 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may refer to “sub 6 GHz range” and FR2 may refer to “above 6 GHz range” and may be called millimeter wave (mmW).

TABLE 4 Frequency Range Corresponding designation frequency range Subcarrier Spacing FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

As described above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 5 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included in FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for a vehicle (e.g., autonomous driving).

TABLE 5 Frequency Range Corresponding designation frequency range Subcarrier Spacing FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on) may be differently configured between a plurality of cells integrated to one UE. Accordingly, an (absolute time) duration of a time resource (e.g., SF, slot or TTI) (for convenience, collectively referred to as a time unit (TU)) configured of the same number of symbols may be differently configured between the integrated cells.

FIG. 17 illustrates a slot structure.

Referring to FIG. 17, a slot includes a plurality of symbols in a time domain. For example, in case of a normal CP, one slot may include 14 symbols. However, in case of an extended CP, one slot may include 12 symbols. Alternatively, in case of the normal CP, one slot may include 7 symbols. However, in case of the extended CP, one slot may include 6 symbols.

A carrier includes a plurality of subcarriers in a frequency domain. A resource block (RB) may be defined as a plurality of consecutive subcarriers (e.g., 12 subcarriers) in the frequency domain. A bandwidth part (BWP) may be defined as a plurality of consecutive (P)RBs in the frequency domain, and the BWP may correspond to one numerology (e.g., SCS, CP length, and so on). The carrier ma include up to N (e.g., 5) BWPs. Data communication may be performed through an activated BWP. Each element may be referred to as a resource element (RE) within a resource grid, and one complex symbol may be mapped thereto.

A physical downlink control channel (PDCCH) may include one or more control channel elements (CCEs) as illustrated in the following table 6.

TABLE 6 Aggregation level Number of CCEs 1 1 2 2 4 4 8 8 16 16

That is, the PDCCH may be transmitted through a resource including 1, 2, 4, 8, or 16 CCEs. Here, the CCE includes six resource element groups (REGs), and one REG includes one resource block in a frequency domain and one orthogonal frequency division multiplexing (OFDM) symbol in a time domain.

A new unit called a control resource set (CORESET) may be introduced in the NR. The UE may receive a PDCCH in the CORESET.

Hereinafter, a BWP will be described.

In the NR system, up to 400 megahertz (MHz) per component carrier (CC) can be supported. If a UE operating in such a wideband CC always operates with RFs for the entire CC turned on, UE battery consumption may increase. Alternatively, considering multiple use cases (e.g., eMBB, URLLC, mMTC, etc.) in which operation is performed within one broadband CC, different numerologies (e.g., subcarrier spacings (SCSs)) may be supported for respective frequency bands within the CC. Alternatively, UEs may have different capabilities for a maximum bandwidth. In consideration of this, a base station may instruct a UE to operate only in a partial bandwidth rather than the entire bandwidth of a broadband CC. This partial bandwidth is defined as a bandwidth part (BWP) for convenience. The BWP may include resource blocks (RBs) consecutive on the frequency axis and may correspond to one numerology (e.g., a subcarrier spacing, a cyclic prefix (CP) length, a slot/mini-slot duration, or the like).

On the other hand, the base station may set a plurality of BWPs even within one CC configured for a UE. For example, a BWP occupying a relatively small frequency region may be set in a PDCCH monitoring slot, and a PDSCH indicated by a PDCCH may be scheduled on a larger BWP. Alternatively, when UEs are concentrated in a specific BWP, some UEs may be set to other BWPs for load balancing. Alternatively, in consideration of frequency domain inter-cell interference cancellation between neighboring cells, a partial spectrum from an entire bandwidth may be excluded and both BWPs may be set in the same slot. That is, the base station may set at least one DL/UL BWP for a UE associated with a wideband CC and activate at least one DL/UL BWP among DL/UL BWP(s) set at a specific time (by L1 signaling, MAC CE, RRC signaling, or the like). Further, switching to another configured DL/UL BWP may be indicated (by L1 signaling, MAC CE, RRC signaling, or the like), or switching to a predetermined DL/UL BWP may be performed when a timer value expires based on a timer. In this case, the activated DL/UL BWP is defined as an active DL/UL BWP. However, a UE may not receive a configuration for the DL/UL BWP when the UE is in an initial access process or before RRC connection is set up, a DL/UL BWP assumed by the UE in this situation is defined as an initial active DL/UL BWP.

Hereinafter, the proposal of the present disclosure will be described in more detail.

The following drawings were created to explain specific examples of the present disclosure. Since the names of specific devices described in the drawings or the names of specific signals/messages/fields are presented by way of example, the technical features of the present disclosure are not limited to the specific names used in the following drawings.

In the NR system, a maximum of four BWPs may be set per serving cell, and a dormant state considers operation in units of BWPs. Accordingly, a dormancy behavior for each cell and BWP needs to be defined.

In the LTE system, a dormant state is defined in order to rapidly perform activation/deactivation of a secondary cell (SCell), and when a specific SCell is set to a dormant state, a UE may not monitor a PDCCH for the cell. Thereafter, in order to rapidly activate the corresponding SCell, it is defined that measurement and reporting are performed in the dormant state to monitor the channel condition and link status of the corresponding cell. For example, when a specific SCell is set to a dormant state, a UE does not perform PDCCH monitoring but may perform measurement and reporting for channel state information (CSI)/radio resource management (RRM). In the NR system, the aforementioned dormant state or a dormancy behavior may be defined in units of BWP.

For example, a dormancy behavior for each cell and BWP may be defined through the following methods. Meanwhile, in the present disclosure, a dormancy behavior may be cross-interpreted as a UE operation based on a dormant mode, and a normal behavior may be cross-interpreted as an operation other than the dormancy behavior or as a UE operation based on a normal mode.

(Method 1 of Defining Dormancy Behavior) State Change

A network may indicate transition to a dormant state for a specific BWP, and a UE may not perform some or all of PDCCH monitoring set to the BWP for which transition to the dormant state is indicated.

(Method 2 of Defining Dormancy Behavior) Dormant BWP

A network may designate a specific BWP as a dormant BWP. For example, it is possible to instruct PDCCH monitoring not to be performed by configuring a BWP having a bandwidth of 0, indicating minimum PDCCH monitoring through BWP configuration, not indicating a search space set configuration, or the like.

Additionally, the NR system considers switching between a normal state and a dormant state through L1 signaling such as DCI for faster SCell activation/deactivation. For example, a dormancy behavior of a specific cell may be activated/deactivated through the following methods.

(Activation Method 1) Introduction of Special DCI

Special DCI for indicating a dormancy behavior of each SCell may be defined. For example, a UE may be instructed to monitor special DCI in a PCell, and a network may determine whether dormancy is set for each SCell through the special DCI. The dormancy behavior of the SCell may be defined using the aforementioned method 1, method 2, or the like.

(Activation Method 2) Enhancement of BWP Indication Field in DCI

A BWP indication field of the existing DCI may be extended to perform BWP indication of the corresponding cell and/or specific SCell(s). That is, cross-carrier indication for a BWP may be performed through the existing BWP indication field.

(Activation Method 3) BWP Cross-Carrier Scheduling

Conventional cross-carrier scheduling indicates whether a cell is a scheduling cell or a scheduled cell, and in the case of a scheduled cell, performs pairing between carriers by indicating a scheduling cell of the scheduled cell. In order to define a dormancy behavior for an SCell, a method of indicating whether cross-carrier scheduling is performed for each BWP may also be considered. For example, in each BWP configuration of the SCell, a scheduling cell that can indicate state transition when a dormancy behavior is performed in the corresponding BWP may be designated. Alternatively, when a dormant BWP is designated, a scheduling cell that indicates a dormancy behavior in the corresponding BWP may be designated in the corresponding BWP configuration.

As described above, various methods for implementing fast activation/deactivation, and dormancy behavior of the SCell in NR are under discussion. When the above-mentioned methods are used, the following needs to be additionally considered.

(Issue 1) Default BWP triggered by a BWP inactivity timer

(Issue 2) Scheduling information in DCI triggering dormancy behavior

(Issue 3) HARQ feedback of DCI triggering dormancy behavior

The considerations and solutions will be described below.

In the present disclosure, a D-BWP may mean a BWP in which a dormancy behavior is performed, and an N-BWP is a normal BWP and may mean a BWP in which the conventional BWP operation is performed. In addition, in the present disclosure, a dormancy behavior in a certain BWP may mean an operation in which a PDCCH is not received in the BWP or is received in a longer period than in a normal behavior, or an operation in which PDSCH/PUSCH scheduling for the BWP is not performed or is performed in a period longer than the normal behavior. Similarly, the dormant BWP may mean a BWP in which a PDCCH is not received or is received in a longer period than in the normal behavior, or PDSCH/PUSCH scheduling for the BWP is not performed or is performed in a longer period than in the normal BWP.

FIG. 18 shows an example of a dormancy behavior. Specifically, (a) and (b) of FIG. 18 show examples of an operation according to indication of a dormant state of a UE.

Referring to (a) of FIG. 18, the UE performs PDCCH monitoring in a first BWP based on a normal behavior. Thereafter, when the UE receives a dormant state indication, the UE does not perform PDCCH monitoring.

Referring to (b) of FIG. 18, the UE performs PDCCH monitoring in a second BWP based on the normal behavior. Here, PDCCH monitoring may be periodically performed based on a first period. Thereafter, when the UE receives dormant state indication, the UE periodically performs PDCCH monitoring based on a second period. In this case, the second period may be longer than the first period.

Hereinafter, a default BWP triggered by a BWP inactivity timer will be described.

In relation to the BWP operation, a BWP inactivity timer has been introduced in the NR system in order to prevent a case in which different active BWPs are configured due to misunderstanding between a UE and a network. If the UE does not receive a PDCCH for more than a specific time designated by a timer in an active BWP, the UE can move to a default BWP indicated in advance by the network and perform PDCCH monitoring in the default BWP according to PDCCH monitoring configuration such as CORESET and search space set configuration for the default BWP.

FIG. 19 shows an example of a BWP operation.

Referring to FIG. 19, when a UE does not receive a PDCCH for a time set by the BWP inactivity timer in a first BWP while receiving the PDCCH on the first BWP, the UE moves to a second BWP that is a default BWP and performs PDCCH monitoring.

Meanwhile, in the present disclosure including FIG. 19, moving from the first BWP to the second BWP may mean that an active BWP is changed from the first BWP to the second BWP.

When a default BWP operation and a dormancy behavior are performed together, operations inconsistent with the purposes thereof may be performed. For example, the network may instruct a specific SCell to move to a D-BWP or to switch the current BWP to a dormant state for power saving of a UE. However, the UE for which a BWP inactivity timer is configured may move to the default BWP after a certain period of time and perform PDCCH monitoring.

A simple way to solve this is to consider setting the default BWP to a D-BWP. However, in this case, an additional method for resolving misunderstanding between the network and the UE, which is the original purpose of the default BWP, is required. In the present disclosure, the following method is proposed in order to apply the dormancy operation and the BWP inactivity timer together.

When the network instructs a UE to move to a D-BWP or switches the current active BWP to a dormant state, the UE may ignore a previously set BWP inactivity timer or reset the BWP inactivity timer to a predefined value or a value indicated by the network in relation to the dormant state. For example, the network may set an appropriate dormancy period in consideration of the traffic condition of the UE and indicate the corresponding value to the UE in advance. Thereafter, when the UE is instructed to move to a D-BWP or to switch the current active BWP to a dormant state, the UE may set a value indicated by the network as a BWP inactivity timer value. In addition, an inactivity timer for the dormancy behavior indicated by the network may operate independently of the existing BWP inactivity timer. For example, a UE instructed to perform a dormancy behavior may turn off the existing BWP inactivity timer and operate the inactivity timer for the dormancy behavior. Thereafter, when the BWP inactivity timer expires or the UE is instructed to move to an N-BWP or to switch to a normal state, the UE may end the dormancy behavior.

In addition, when the dormancy behavior ends by the inactivity timer for the dormancy behavior, the UE may move to a default BWP of the corresponding cell or switch to a normal state. Alternatively, when the network ends the dormancy behavior by the inactivity timer, the network may designate a BWP to which the UE will move and indicate the BWP to the UE.

FIG. 20 shows another example of the BWP operation of a UE. Specifically, FIG. 20 shows an example of a case in which the UE is instructed/configured to switch to a dormant state while the BWP inactivity timer is in operation in the example of FIG. 19.

Referring to FIG. 20, the UE receives a dormant state transition message during the operation of the BWP inactivity timer on a first BWP. The dormant state transition message may be a message for instructing the UE to switch to a dormant state.

The inactivity timer for the dormancy operation may start upon reception of the dormant state transition message by the UE. Here, if the inactivity timer for the dormancy behavior expires, the UE may perform PDCCH monitoring on a second BWP, which is a default BWP.

Hereinafter, scheduling information in DCI which triggers a dormancy behavior will be described.

When movement between a D-BWP and an N-BWP is indicated by DCI or the like, and the DCI is normal scheduling DCI, a problem may occur if it is not clear whether an operation for scheduling information in the DCI is performed. For example, when an operation for PDSCH scheduling in DCI indicating movement to a D-BWP is performed, an additional operation may be required depending on whether reception of the corresponding PDSCH is successful. This may mean that PDCCH/PDSCH transmission/reception operations may continue even in the D-BWP. In order to solve such a problem, the present disclosure proposes the following method.

(Case 1-1) Case in which DCI Indicating a Dormancy Behavior for a Specific Cell or DCI Indicating Switching to a Dormant BWP Includes PDSCH Scheduling Information

As described above, since PDSCH transmission/reception in a D-BWP may cause additional PDCCH/PDSCH transmission/reception, an operation contrary to the purpose of the dormant BWP may be performed. Accordingly, PDSCH scheduling information for a D-BWP included in DCI indicating a dormancy behavior may be ignored. In addition, the decoding performance of a UE may be improved by transmitting a known bit or a known bit sequence in the corresponding field. To this end, known bit information on a field related to PDSCH scheduling may be indicated by a network or through previous definition.

(Case 1-2) Case in which in DCI Indicating Transition from a Dormancy Behavior to a Normal Behavior or DCI Indicating Transition from a Dormant BWP to a Normal BWP Includes PDSCH Scheduling or Uplink Scheduling Information

In case 1-2, since PDSCH scheduling information or uplink scheduling information can reduce PDCCH transmission in a N-BWP or in a normal state, it may be desirable to apply the information. However, in case 1-2, determination of whether to apply PDSCH scheduling information or uplink scheduling information may be limited to a case in which the PDSCH scheduling information or uplink scheduling information is UL/DL scheduling related information in a N-BWP in which transition occurs or PDSCH or uplink transmission related information in a normal state. For example, when a field indicating a dormancy behavior for specific SCell(s) is added to DCI for scheduling a PDSCH of a PCell, PDSCH scheduling information of the DCI may mean PDSCH related information in the PCell.

Hereinafter, HARQ feedback of DCI that triggers a dormancy behavior will be described.

Since the dormancy behavior can limit PDCCH/PDSCH transmission and reception operations in an indicated cell (according to definition) as much as possible, subsequent operations of a network and a UE may be greatly affected by missing/false alarm, and the like. In order to solve this, a method for improving decoding performance may be applied or an additional confirmation operation for dormancy behavior indication may be required. To solve this problem, the present disclosure proposes ACK/NACK feedback for movement to a D-BWP or transition to a dormant state. To this end, the following methods may be considered. The methods which will be described below may be implemented alone or in combination. In the following description, when DCI is configured only with an indication for a dormancy behavior, a UE cannot determine whether or not NACK is provided, and thus the proposal below may be interpreted as transmitting ACK signaling. Alternatively, when DCI indicating a dormancy behavior also includes PDSCH scheduling, it may mean that ACK/NACK for the corresponding PDSCH or uplink transmission in the case of uplink scheduling is performed upon reception of a command for the dormancy behavior. That is, since both ACK and NACK may indicate that DCI has been normally received, both ACK and NACK may indicate that an indication for the dormancy behavior has been received.

(Case 2-1) Combination of Dormancy Command and UL/DL Scheduling

DCI indicating a dormancy behavior may include uplink/downlink scheduling information, and ACK/NACK for downlink and scheduled uplink transmission may mean that DCI including a dormancy behavior has been properly received, and thus a UE and a network may assume that the indicated dormancy behavior is to be performed. Here, since NACK means NACK for PDSCH reception, NACK may also mean that an indication for a dormancy behavior has been received.

(Case 2-1-1) Case in which a Target of Uplink/Downlink Scheduling is a Dormant BWP or a Dormant State

It may be assumed that a UE can perform a dormancy behavior after termination of up to scheduled uplink/downlink scheduling and ACK/NACK resources or uplink resources for the corresponding scheduling in a D-BWP or a dormant state conform to the conventional ACK/NACK resource determination method and uplink transmission method. The UE that has completed corresponding uplink/downlink transmission/reception may perform a dormancy behavior and may assume that subsequent scheduling is not present or ignore subsequent scheduling.

(Case 2-1-2) Case in which a Target of Uplink/Downlink Scheduling is a Scheduling Cell/BWP or a Normal State

In this case, ACK/NACK or uplink transmission may mean that a dormancy command has been normally received in the scheduling cell/BWP or normal state, and a UE may perform a dormancy behavior.

(Case 2-2) Combination of Dormancy Command and Non-Scheduling/Fake-Scheduling

Case 2-2 is a case in which a dormancy behavior is indicated by DCI in which only a command for a dormancy behavior is valid without uplink/downlink scheduling information or DCI in which a scheduling information field can be assumed as dummy/dummy data. In this case, feedback information for the DCI may be transmitted because there is no associated uplink/downlink transmission/reception. Here, when DCI is not received, the UE does not ascertain whether the DCI is transmitted, and thus it may actually mean ACK transmission. In this case, feedback for the dormancy command may be transmitted in a dormant BWP or a dormant state, and feedback resources may be indicated by the DCI carrying the dormancy command or feedback may be performed through predefined feedback resources.

Hereinafter, BWP determination for a normal state will be described.

When transition between a normal BWP and a dormant BWP is performed only by changing states without BWP indication, for example, when a network allocates 1 bit to DCI transmitted from a PCell per SCell or per SCell group to indicate only dormancy, a BWP for dormant mode/normal mode is predefined. As an example, the network may designate one BWP (D-BWP) for the dormant mode, and if a predefined 1-bit field in DCI is “1” or “0”, designate an active BWP of an associated SCell as a D-BWP. In the case of a dormant BWP, since a plurality of dormant BWPs only increase signaling overhead and have no additional gain, it may be desirable to designate only one dormant BWP per cell. On the other hand, in the case of a general BWP, a maximum of 4 BWPs per cell may be designated as in the conventional scheme. This may mean that, when transition from the dormant mode to the normal mode occurs, movement to one of configured normal BWPs is required. The present disclosure proposes a method of selecting an active BWP in the normal mode when a UE is instructed to switch from the dormant mode to the normal mode.

(Option 1-1) Active BWP in Normal Mode Immediately Before Dormant Mode

As a first method, an active BWP in the normal mode before entering the dormant mode may be assumed to be an active BWP in the normal mode after the dormant mode. This may be useful when a time during which the dormant mode is maintained is relatively short.

(Option 1-2) Default BWP or BWP Predefined by Network

When a UE switches from the dormant mode to the normal mode, the UE may move to a default BWP designated in the corresponding cell. In this case, the default BWP may be a default BWP to which the UE will move when a BWP inactivity timer expires, or a BWP designated by the network using higher layer signaling, or the like for an SCell dormancy behavior. When the network wants to operate a UE in a wider BWP or a narrower BWP than the default BWP, the network can move the BWP in the normal mode through the conventional BWP switching procedure.

A method to be actually applied between the aforementioned options 1-1 and 1-2 may be designated by previous definition or may be configured by the network through higher layer signaling or the like. Alternatively, an option to be applied may be determined by additionally designating a timer or the like. For example, at the time of changing from the dormant mode to the normal mode, if a predefined timer has not expired, a UE may move to the last active BWP in the normal mode immediately before the dormant mode according to option 1-1. After the timer expires, the UE instructed to switch to the normal mode may move to a default BWP and perform the normal mode.

Hereinafter, the maximum number of BWPs per cell will be described.

In the conventional BWP operation, a maximum of 4 BWPs per cell can be configured for a UE. On the other hand, when the dormant BWP is introduced, the limit may need to be adjusted. The present disclosure proposes a method for designating the maximum number of BWPs in a cell in which a dormant BWP is designated.

(Option 2-1) the Maximum Number of BWPs is Increased by 1 if Dormant BWPs are Designated.

With respect to dormant BWPs, increase in the maximum number of BWPs per cell due to dormant BWPs may not be a major issue because a UE has little hardware/software impact. Therefore, in a cell in which dormant BWPs are designated, the same operation as the previous operation can be maintained by increasing the maximum number of BWPs by 1.

(Option 2-2) Dormant BWPs are not Included in the Number of BWPs.

As described above, on a dormant BWP, a UE does not perform most of operations performed in the conventional BWP. Accordingly, dormant BWPs are not included in the number of BWPs.

Hereinafter, HARQ feedback for dormancy indication will be described.

As described above, the dormancy behavior may limit PDCCH/PDSCH transmission and reception operations in an indicated cell (according to the definition) to the maximum, and thus subsequent operations of a network and a UE may be significantly affected by missing/false alarm and the like. To solve this, a method for increasing decoding performance may be applied or an additional confirmation operation for dormancy behavior indication may be required. Hereinafter, in order to solve such a problem, an ACK/NACK feedback method for dormancy indication is proposed. Although an ACK/NACK feedback method for a dormancy behavior of an SCell in a PCell will be described below, this method may be equally applied even when the SCell indicates a dormancy behavior for another SCell.

As a method of indicating a dormancy behavior of an SCell in a PCell, a method of appending dormancy behavior indication field for the SCell to DCI that schedules a PDSCH of the PCell or indicating a dormancy behavior for the SCell by reinterpreting some fields in the DCI that schedules the PDSCH of the PCell may be considered. In this case, the following two cases can be considered according to the role of DCI. Hereinafter, an ACK/NACK feedback method for dormancy indication for each case will be described.

(Case 3-1) Combination of PDSCH Scheduling Information and SCell Dormancy Indication

In case 3-1, ACK/NACK for a PDSCH scheduled along with dormancy indication may also be interpreted as ACK/NACK for dormancy indication. However, since NACK may be transmitted even when DCI is missed for the PDSCH, for example, a plurality of PDSCHs may be scheduled and HARQ-ACK feedbacks for the PDSCHs may be transmitted in one PUCCH resource, there may be a problem that it is not possible to distinguish whether the corresponding NACK is NACK due to DCI missing or NACK indicating that DCI is received, that is, dormancy indication is received, but decoding of PDSCHs has failed. To solve this problem, a method of transmitting ACK/NACK information corresponding to a PDSCH and ACK/NACK information for dormancy indication are transmitted through the same PUCCH resource is proposed. Specifically, ACK/NACK information corresponding to a PDSCH and ACK/NACK information for dormancy indication may be fed back/transmitted together through a slot after K1 slots indicated by HARQ-ACK feedback timing through the DCI from the DCI or the corresponding PDSCH. More specifically, the ACK/NACK information corresponding to the PDSCH may configure a semi-static or dynamic HARQ-ACK codebook in the same way as in the legacy NR system, and then append 1-bit HARQ-ACK corresponding to dormancy indication to a specific position in the corresponding HARQ-ACK codebook, such as the last digit or the highest bit index corresponding thereto, for example. That is, case 3-1 may mean a method of appending an ACK/NACK field (e.g., a 1-bit field) for dormancy indication to the existing ACK/NACK reporting procedure for PDSCH scheduling indicated along with the dormancy indication. Alternatively, 1-bit HARQ-ACK corresponding to dormancy indication may be transmitted in the next digit in the codebook of the HARQ-ACK bit corresponding to the PDSCH, or the 1-bit HARQ-ACK corresponding to the dormancy indication may be transmitted in a specific position of a HARQ-ACK payload corresponding to a cell to which the PDSCH is transmitted in the codebook, for example, the last digit or the highest bit index corresponding thereto.

Alternatively, the UE may not expect PDSCH scheduling for a corresponding SCell in a slot in which the SCell switches a dormant state or a plurality of slots including the corresponding slot. In this case, HARQ-ACK for dormancy indication for the SCell may be transmitted at a position where HARQ-ACK information for the SCell of the corresponding timing is transmitted in the HARQ-ACK codebook for dormancy indication transmitted to a corresponding PCell for semi-static codebook, and the like. Here, if the dormancy indication is an indication for an SCell group consisting of a plurality of SCells, the same feedback may be transmitted at all HARQ-ACK positions for the corresponding SCells, or feedback may be transmitted at a HARQ-ACK position for a specific SCell such as an SCell having the lowest index. In addition, the feedback may be transmitted as the same value for a plurality of slot timings at which PDSCH scheduling is not expected to the SCell.

Meanwhile, a semi-static codebook and a dynamic codebook in the present disclosure may mean a type-1 codebook and a type-2 codebook based on NR.

(Case 3-2) SCell Dormancy Indication without PDSCH Scheduling Information

According to case 3-2, since there is no PDSCH scheduling indicated along with dormancy indication, ACK/NACK for a PDCCH, that is, dormancy indication needs to be transmitted. For this, the following methods may be considered.

(ACK/NACK transmission method 1) After a HARQ-ACK codebook based on NR is configured, such as a case in which a semi-static HARQ-ACK codebook is configured, a HARQ-ACK field for dormancy indication may be appended to a specific position. Here, the specific position may be the last digit or the highest bit index corresponding thereto, and the appended HARQ-ACK field may be a 1-bit field, for example.

(ACK/NACK transmission method 2) When the semi-static HARQ-ACK codebook is configured, similarly to the HARQ-ACK feedback method for DCI indicating SPS release of NR, a UE may assume that there is no other unicast PDSCH reception within the same slot as the slot in which a PDCCH indicating a dormant state is transmitted when HARQ-ACK is transmitted in corresponding DCI within the semi-static HARQ-ACK codebook or at a position corresponding to a slot in which the DCI is transmitted.

(ACK/NACK transmission method 3) In the same manner as in case 3-1, HARQ-ACK for dormancy indication may be transmitted at a HARQ-ACK position corresponding to the SCell within the HARQ-ACK codebook.

Hereinafter, HARQ-ACK feedback timing will be described.

In the above description, the HARQ-ACK feedback timing for dormancy indication may be determined as follows.

(Option 3-1) Slots after K1 Slots from DCI

A slot after K1 from a slot in which DCI including dormancy indication has been transmitted, i.e., after a slot offset between DCI and HARQ-ACK may be determined.

(Option 3-2) K1 Slots from PDSCH Scheduled by DCI

A network may determine a slot after K1 slots from a PDSCH position based on PDSCH resource allocation information in DCI including dormancy indication as a feedback timing. In case 3-2, although there is no PDSCH that is actually scheduled, the network may allocate a virtual PDSCH to deliver the HARQ-ACK feedback timing for dormancy indication.

The above-mentioned proposal may be applied only when a candidate PDSCH reception slot associated with an uplink channel carrying HARQ-ACK information or a PDCCH monitoring occasion corresponding thereto includes a monitoring occasion for a PDCCH indicating a dormant state. In addition, case 3-1 may be applied to only cases other than fallback PUCCH transmission, that is, a case in which HARQ-ACK information to be actually fed back is 1 bit corresponding only to a single PCell single PDSCH (in the case of a semi-static codebook) or corresponds to a single PDSCH with counter-DAI=1. In other words, in the case of fallback PUCCH transmission, only HARQ-ACK for a scheduled PDSCH may be fed back without additional HARQ-ACK feedback for dormancy indication.

The UE that has derived a slot offset through the above-described method needs to determine a start and length indicator value (SLIV) in a PDSCH slot corresponding to K1, to which HARQ-ACK will be mapped. To this end, the present disclosure proposes a method of mapping corresponding HARQ-ACK to a virtual SLIV indicated by DCI or a specific SLIV candidate such as the first or last candidate, for example. This method may be applied when the HARQ-ACK codebook is configured in the ACK/NACK transmission method 2, particularly in case 3-2.

Additionally, in the case of a semi-static codebook, a HARQ-ACK set corresponding to the current active downlink BWP of an activated cell and the first active downlink BWP of a deactivated cell is fed back. When the active downlink BWP of a specific cell is a dormant BWP, a HARQ-ACK codebook corresponding to the cell may be configured through the following method. In addition, the following methods may be applied from X ms after a dormant BWP is indicated, and the value X may be determined by previous definition or higher layer signaling of a network.

(Option 4-1) HARQ-ACK Corresponding to the First Active Downlink BWP and an SLIV and a Set of K1 Values Configured Therein as in a Deactivated Cell

(Option 4-2) 0 Bits

(Option 4-3) HARQ-ACK Corresponding to the Latest BWP Immediately Before the Corresponding Dormant BWP and an SLIV and a Set of K1 Values Configured Therein

In addition to the above-described method, HARQ-ACK codebook configuration may conform to dormant BWP configuration when switching of a dormancy behavior is performed through switching between a BWP (dormant BWP) corresponding to a dormancy behavior and a BWP (non-dormant BWP) corresponding to a non-dormancy behavior. Alternatively, if there are no configurations for HARQ-ACK codebook configuration, such as a time domain resource assignment (TDRA) table and an SLIV table in dormant BWPs, it is possible to conform to the configuration of a specific BWP of the corresponding cell. Here, the specific BWP may be a BWP having the lowest/highest index BWP excluding dormant BWPs, a configured reference BWP, an initial BWP, the latest non-dormant active BWP, and the like, for example.

In the above-described methods, when a UE receives dormancy indication again before a dormancy/non-dormancy behavior according to dormancy indication is applied to the same SCell, the UE may follow the most recently received dormancy indication, or consider that an error has been generated in reception of corresponding DCI if two dormancy indications indicate different behaviors on the assumption that the two dormancy indications indicate the same behavior (dormancy or non-dormancy).

Alternatively, when the UE receives dormancy indication for an SCell, the UE may assume that dormancy indication for the corresponding cell is not transmitted before the corresponding dormancy/non-dormancy behavior is applied or before a specific time period, or may not receive dormancy indication.

Although a case where dormancy indication is transmitted along with downlink scheduling information has been mainly described above, dormancy indication can also be transmitted in uplink scheduling DCI. In the following, a feedback method for confirming whether a UE has correctly received dormancy indication when the dormancy indication is transmitted in uplink scheduling DCI is proposed. Here, feedback for dormancy indication may be transmitted only when the UE detects indication different from the previous indication, for example, when the UE has previously received dormancy indication but subsequently detects normal behavior indication, the UE has previously received normal behavior indication but subsequently detects dormancy indication, and a normal behavior instruction has been previously received but thereafter dormant. When an indication is detected, and the UE has received indication for a specific SCell but subsequently receives indication for an SCell group.

(Feedback Method 1) Method of Using PUSCH

In the NR system, DCI format 0_1 (uplink non-fallback DCI) may include a PUSCH resource allocation field, a UL-SCH indicator field, and a CSI request field. In this case, CSI reporting and related operations of a UE may be as follows. Hereinafter, a HARQ-ACK feedback method for dormancy indication for each operation of each UE is proposed.

(Feedback Method 1-1) when a UL-SCH Indicator is OFF and a CSI Request is ON, a UE Performs Aperiodic CSI Report Through a PUSCH.

In this case, when the UE performs CSI report, a gNB can recognize that the UE has received DCI, that is, DCI including dormancy indication, and thus additional dormancy indication related feedback may not be required.

(Feedback Method 1-2) when the UL-SCH Indicator and the CSI Request are OFF, the UE does not Perform PUSCH Transmission for CSI Report and Only Performs Downlink Measurement.

In this case, the UE may transmit a PUSCH to notify whether the dormancy indication is received. Here. The PUSCH may be a PUSCH with null contents.

Since the above-described method may not be distinguished from the conventional operation of performing only downlink measurement, the network may indicate transmission of DCI based on dormancy indication instead of downlink measurement using a specific field in the DCI or a combination with specific field(s), and the UE may transmit a PUSCH or a PUSCH with null contents according to PUSCH scheduling of the DCI. Here, the specific field may be an additional 1-bit field indicating that the corresponding DCI is DCI dedicated for dormancy indication or may be an existing field set to a specific value, for example, a resource allocation field set to 1.

Alternatively, in order to distinguish from the conventional operation of performing only downlink measurement, the UE may transmit a PUSCH or a PUSCH with null contents according to PUSCH scheduling of the corresponding DCI when the gNB indicates a dormancy behavior or a normal behavior for an arbitrary SCell. In this case, downlink measurement may not be performed.

That is, when uplink grant DCI indicates that dormancy indication is ON and both the UL-SCH indicator and CSI report trigger are OFF according to the above-described method, a signal may be transmitted through PUSCH resources allocated by the DCI. On the other hand, when dormancy indication is OFF and both the UL-SCH indicator and CSI report trigger are OFF, PUSCH transmission corresponding to the DCI may be configured not to be performed.

(Feedback Method 2) Method of Using HARQ-ACK Feedback Mechanism

When the UL-SCH indicator is OFF and the CSI request is OFF, the UE may transmit explicit feedback for dormancy indication.

Since this method may not be distinguished from the conventional operation of performing only downlink measurement, the network may indicate DCI transmission for dormancy indication rather than downlink measurement using a combination with specific field(s) in DCI, and the UE may transmit feedback for the dormancy indication using explicit feedback.

Here, the explicit feedback may be performed in such a manner that, when HARQ-ACK for other PDSCHs is fed back in the corresponding slot, feedback for the dormancy indication is performed by adding 1 bit. Here, if there is no HARQ-ACK feedback for other PDSCHs, feedback for the dormancy indication may be performed using a PUCCH, and PUCCH resources therefor may be preset by RRC signaling, set through an uplink grant, or set through a combination of signaling and the uplink grant. That is, when dormancy indication is transmitted through uplink grant DCI, a feedback transmission timing and PUCCH transmission resources to be used or applied for transmission of feedback for the corresponding dormancy indication may be indicated through fields in the DCI or reinterpretation of the fields in the DCI.

FIG. 21 is a flowchart of an example of a discontinuous reception method of a UE.

Referring to FIG. 21, the UE performs PDCCH monitoring on on-duration (S2110).

In addition, the UE receives BWP configuration information (S2120). Here, the BWP configuration information may indicate a specific BWP.

The UE receives a PDCCH based on PDCCH monitoring (S2130). Here, the PDCCH may include dormancy indication information for a specific cell among a plurality of cells configured for the UE.

Thereafter, the UE activates the specific BWP based on the dormancy indication information indicating non-dormancy (S2140).

Hereinafter, discontinuous reception (DRX) will be described.

Discontinuous reception (DRX) refers to an operation mode in which a UE reduces battery consumption and thus can discontinuously receive a downlink channel. That is, a UE configured for DRX can reduce power consumption by discontinuously receiving a DL signal.

The DRX operation is performed within a DRX cycle indicating a time interval in which on duration is periodically repeated. The DRX cycle includes an on duration and a sleep period (or a DRX occasion). The on duration indicates a time interval in which a UE monitors a PDCCH in order to receive the PDCCH.

DRX may be performed in a radio resource control (RRC)_IDLE state (or mode), RRC_INACTIVE state (or mode), or RRC_CONNECTED state (or mode). In RRC_IDLE state and RRC_INACTIVE state, DRX may be used to discontinuously receive a paging signal.

-   -   RRC_IDLE state: a state in which a radio connection (RRC         connection) is not established between a base station and a UE     -   RRC_INACTIVE state: a state in which a radio connection (RRC         connection) is established between a base station and a UE, but         the radio connection is inactive     -   RRC_CONNECTED state: a state in which a radio connection (RRC         connection) is established between a base station and a UE

DRX can be basically divided into idle mode DRX, connected DRX (C-DRX), and extended DRX.

DRX applied in an IDLE state may be referred to as idle mode DRX, and DRX applied in a connected state may be referred to as connected mode DRX (C-DRX).

Extended/enhanced DRX (eDRX) is a mechanism that can extend the cycles of idle mode DRX and C-DRX and can be mainly used for (massive) IoT applications. In idle mode DRX, whether to allow eDRX may be set based on system information (e.g., SIB1). SIB1 may include an eDRX-allowed parameter. The eDRX-allowed parameter indicates whether idle mode extended DRX is allowed.

Hereinafter, idle mode DRX will be described.

In the idle mode, a UE may use DRX to reduce power consumption. One paging occasion (PO) is a subframe in which a paging-radio network temporary identifier (P-RNTI) can be transmitted through a physical downlink control channel (PDCCH), an MTC PDCCH (MPDCCH) or a narrowband PDCCH (NPDCCH) (which addresses a paging message for NB-IoT).

In the P-RNTI transmitted through an MPDCCH, a PO may indicate a start subframe of MPDCCH repetition. In the case of P-RNTI transmitted through an NPDCCH, if a subframe determined by a PO is not a valid NB-IoT downlink subframe, the PO may indicate a start subframe of NPDCCH repetition. Accordingly, the first valid NB-IoT downlink subframe after the PO is the start subframe of NPDCCH repetition.

One paging frame (PF) is one radio frame that may include one or a plurality of paging occasions. When DRX is used, a UE only needs to monitor one PO per DRX cycle. One paging narrow band (PNB) is one narrow band in which a UE performs paging message reception. PF, PO, and PNB may be determined based on DRX parameters provided by system information.

FIG. 22 is a flowchart illustrating an example of performing an idle mode DRX operation.

Referring to FIG. 22, a UE may receive idle mode DRX configuration information from a base station through higher layer signaling (e.g., system information) (S21).

The UE may determine a paging frame (PF) and a paging occasion (PO) in order to monitor a PDCCH in a paging DRX cycle based on the idle mode DRX configuration information (S22). In this case, the DRX cycle may include an on duration and a sleep duration (or DRX occasion).

The UE may monitor the PDCCH in the PO of the determined PF (S23). Here, the UE monitors only one subframe (PO) per paging DRX cycle, for example. In addition, when the UE receives a PDCCH scrambled by the P-RNTI for the on duration (i.e., when paging is detected), the UE may perform transition to a connected mode and transmit/receive data to/from the base station.

FIG. 23 illustrates an example of an idle mode DRX operation.

According to FIG. 23, when there exists traffic directed toward the UE in the RRC_IDLE state (hereinafter, referred to as ‘idle state’), paging is generated with respect to the corresponding UE. The UE may wake up periodically (namely, every (paging) DRX periods) to monitor a PDCCH. In the absence of paging, the UE may transition to the connected state, receive data, and enter the sleep mode again if there exists no data.

In what follows, Connected mode DRX (C-DRX) is described.

C-DRX refers to DRX applied in the RRC connected state. The DRX cycle for C-DRX may be composed of a short DRX cycle and/or a long DRX cycle. Here, a short DRX cycle may be selected optionally.

When C-DRX is configured, the UE may perform PDCCH monitoring with respect to On Duration. If a PDCCH is successfully detected during PDCCH monitoring, the UE operates (or runs) an inactive timer and maintain the timer in the awake state. On the other hand, if a PDCCH is not detected successfully during PDCCH monitoring, the UE may enter the sleep state after the On Duration expires.

When C-DRX is configured, a PDCCH reception occasion (for example, a slot having PDCCH search space) may be configured to be discontinuous based on the C-DRX configuration. On the other hand, if C-DRX is not configured, the PDCCH reception occasion (for example, a slot having PDCCH search space) may be configured to be continuous according to the present disclosure.

Meanwhile, PDCCH monitoring may be limited to a time interval configured in terms of a measurement gap regardless of the C-DRX configuration.

FIG. 24 illustrates an example of a DRX cycle.

Referring to FIG. 24, the DRX cycle includes an ‘on duration (hereinafter, also referred to as a ‘DRX-on duration’) and an ‘opportunity for DRX’. The DRX cycle defines a time interval in which the on-duration is cyclically repeated. The on-duration indicates a time duration in which a UE performs monitoring to receive a PDCCH. If DRX is configured, the UE performs PDCCH monitoring during the ‘on-duration’. If there is a PDCCH successfully detected during the PDCCH monitoring, the UE operates an inactivity timer and maintains an awake state. On the other hand, if there is no PDCCH successfully detected during the PDCCH monitoring, the UE enters a sleep state after the ‘on-duration’ ends. Therefore, when the DRX is configured, in the performing of the procedure and/or methods described/proposed above, PDCCH monitoring/reception may be performed discontinuously in a time domain. For example, when the DRX is configured, in the present disclosure, a PDCCH reception occasion (e.g., a slot having a PDCCH search space) may be configured discontinuously according to the DRX configuration. Otherwise, if the DRX is not configured, in the performing of the procedure and/or methods described/proposed above, PDCCH monitoring/reception may be performed continuously in the time domain. For example, when the DRX is not configured, in the present disclosure, a PDCCH reception occasion (e.g., a slot having a PDCCH search space) may be configured continuously. Meanwhile, regardless of whether the DRX is configured, PDCCH monitoring may be restricted in a duration configured as a measurement gap.

Table 7 shows a UE procedure related to DRX (RRC_CONNECTED state). Referring to Table 7, DRX configuration information may be received through higher layer (e.g., RRC) signaling. Whether DRX is ON or OFF may be controlled by a DRX command of a MAC layer. If the DRX is configured, PDCCH monitoring may be performed discontinuously.

TABLE 7 Type of signals UE procedure 1^(st) step RRC signalling (MAC- Receive DRX configuration CellGroupConfig) information 2^(nd) step MAC CE ((Long) DRX Receive DRX command command MAC CE) 3^(rd) step — QMonitor a PDCCH during an on- duration of a DRX cycle

MAC-CellGroupConfig may include configuration information required to configure a medium access control (MAC) parameter for a cell group. MAC-CellGroupConfig may also include configuration information regarding DRX. For example, MAC-CellGroupConfig may include information for defining DRX as follows.

-   -   Value of drx-OnDurationTimer: This defines a length of a         starting duration of a DRX cycle. It may be a timer related to a         DRX-on duration.     -   Value of drx-InactivityTimer: This defines a length of a time         duration in which the UE is in an awake state, after a PDCCH         occasion in which a PDCCH indicating initial UL or DL data is         detected.     -   Value of drx-HARQ-RTT-TimerDL: This defines a length of a         maximum time duration until DL retransmission is received, after         DL initial transmission is received.     -   Value of drx-HARQ-RTT-TimerDL: This defines a length of a         maximum time duration until a grant for UL retransmission is         received, after a grant for UL initial transmission is received.     -   drx-LongCycleStartOffset: This defines a time length and a         starting point of a DRX cycle     -   drx-ShortCycle (optional): This defines a time length of a short         DRX cycle.

Herein, if any one of drx-OnDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is operating, the UE performs PDCCH monitoring in every PDCCH occasion while maintaining an awake state.

FIG. 25 is a flowchart of a C-DRX operation.

The UE may receive RRC signaling (for example, MAC-MainConfig IE) including DRX configuration information from a base station S31. Here, DRX configuration information may include the following information.

-   -   onDurationTimer: The number of PDCCH subframes to be monitored         continuously from the starting position of a DRX cycle.     -   drx-InactivityTimer: The number of PDCCH subframes to be         monitored continuously when the UE decodes a PDCCH having         scheduling information.     -   drx-RetransmissionTimer: The number of PDCCH subframes to be         monitored continuously when HARQ retransmission is expected.     -   longDRX-Cycle: The period during which On Duration is generated.     -   drxStartOffset: The subframe number at which a DRX cycle is         started.     -   drxShortCycleTimer: The short DRX cycle number     -   shortDRX-Cycle: A DRX cycle operating as many times as the         number of drxShortCycleTimers when the Drx-InactivityTimer         expires.

Also, when DRX ‘ON’ is configured by the DRX command of the MAC Command Element (CE) S32, the UE monitors the PDCCH with respect to the On Duration of the DRX cycle based on the DRX configuration S33.

FIG. 26 illustrates an example of a C-DRX operation.

If the UE receives scheduling information (for example, a DL grant) in the RRC_CONNECTED state (in what follows, referred to as connected state), the UE may execute the DRX inactive timer and the RRC inactive timer.

When the DRX inactive timer expires, the DRX mode may be started. The UE may wake up from the DRX cycle and monitor the PDCCH for a predetermined time period (on the duration timer). In this case, when short DRX is configured and the UE starts the DRX mode, the UE first starts with a short DRX cycle and after the short DRX cycle is completed, starts a long DRX cycle. Here, the long DRX cycle may correspond to a multiple of the short DRX cycle. Moreover, during the short DRX cycle, the UE may wake up more often. After the RRC inactive timer expires, the UE may transition to the IDLE state and perform the IDLE mode DRX operation.

FIG. 27 illustrates power consumption depending on the state of a UE.

Referring to FIG. 27, after the UE is turned on, the UE performs booting up for application loading, an initial access/random access procedure for uplink and downlink synchronization with a base station, and a registration procedure with respect to a network. The current or power consumed during each procedure are shown in FIG. 27. When the transmission power of the UE is high, the current consumption of the UE increases. In addition, if there is no traffic to be transmitted to the UE or to the base station, the UE switches to the idle mode to reduce power consumption and performs an idle mode DRX operation. Further, when paging, such as a call occurrence, occurs during the idle mode DRX operation, the UE switches from the idle mode to the connected mode through a cell establishment procedure and transmits/receives data to/from the base station.

In addition, the UE performs a connected mode DRX (C-DRX) operation when there is no data transmitted/received to/from the base station for a specific time or at a set timing in the connected mode.

Further, when extended DRX (eDRX) is configured through higher layer signaling such as system information, the UE may perform the eDRX operation in the idle mode or the connected mode.

The claims described in the present disclosure may be combined in various manners. For example, the technical features of the method claims of the present disclosure may be combined and implemented as an apparatus, and the technical features of the apparatus claims of the present disclosure may be combined and implemented as a method. In addition, the technical features of the method claims of the present disclosure and the technical features of the apparatus claims may be combined and implemented as an apparatus, and the technical features of the method claims of the present disclosure and the technical features of the apparatus claims may be combined and implemented as a method.

In addition to a UE, the methods proposed in the present disclosure may be performed by an apparatus configured to control the UE, which includes at least one computer-readable recording medium including an instruction based on being executed by at least one processor, one or more processors, and one or more memories operably coupled by the one or more processors and storing instructions, wherein the one or more processors execute the instructions to perform the methods proposed in the present disclosure. Further, it is obvious that an operation of a base station corresponding to an operation performed by the UE may be considered according to the methods proposed in the present disclosure. 

What is claimed is:
 1. A method for a discontinuous reception (DRX) operation performed by a user equipment (UE) for which a plurality of cells is configured in a wireless communication system, the method comprising: performing a physical downlink control channel (PDCCH) monitoring in on-duration; receiving bandwidth part (BWP) configuration information, the BWP configuration information indicating a specific BWP; receiving a PDCCH based on PDCCH monitoring, the PDCCH including dormancy indication information with respect to a specific cell among the plurality of cells for the UE; transmitting ACK/NACK (acknowledgement/negative-acknowledgement) information for the PDCCH including the dormancy indication information; and activating the specific BWP based on the dormancy indication information indicating non-dormancy.
 2. The method of claim 1, wherein the UE receives the PDCCH on a primary cell.
 3. The method of claim 1, wherein an active BWP of the UE is a dormant BWP before the PDCCH is received.
 4. The method of claim 3, wherein the UE does not perform physical downlink control channel (PDCCH) monitoring or does not receive a physical downlink shared channel (PDSCH) on the dormant BWP.
 5. The method of claim 3, wherein the dormant BWP is a BWP set by higher layer signaling.
 6. The method of claim 1, wherein a field by which the dormancy indication information indicates non-dormancy is 1 bit.
 7. The method of claim 1, wherein a maximum number of BWPs configurable for the specific cell for the UE is four.
 8. The method of claim 1, wherein the ACK/NACK information includes ACK information, and does not include NACK information.
 9. The method of claim 1, wherein the ACK/NACK information includes ACK information and NACK information.
 10. The method of claim 1, wherein the UE receives a PDSCH or a PDCCH on the specific BWP.
 11. The method of claim 1, wherein the ACK/NACK information is transmitted in a slot after a specific number of slots from a slot in which the PDCCH is transmitted.
 12. The method of claim 1, wherein the ACK/NACK information is transmitted in a slot after a specific number of slots from a slot in which a physical downlink shared channel (PDSCH) scheduled by the PDCCH is transmitted.
 13. The method of claim 12, wherein the PDSCH is a virtual PDSCH that is not actually scheduled.
 14. The method of claim 1, wherein the plurality of cells includes a primary cell and a secondary cell, wherein the primary cell is a cell in which the UE performs an initial connection establishment procedure or a connection re-establishment procedure, and the secondary cell is a cell in which additional radio resources are provided to the UE.
 15. A user equipment (UE) for which a primary cell and a secondary cell are configured, the UE comprising: one or more memories storing instructions; one or more transceivers; and one or more processors coupling the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to: perform physical downlink control channel (PDCCH) monitoring in on-duration; receive bandwidth part (BWP) configuration information, the BWP configuration information indicating a specific BWP; receive a PDCCH based on PDCCH monitoring, the PDCCH including dormancy indication information with respect to a specific cell among the plurality of cells for the UE; transmit ACK/NACK (acknowledgement/negative-acknowledgement) information for the PDCCH including the dormancy indication information; and activate the specific BWP based on the dormancy indication information indicating non-dormancy.
 16. An apparatus configured to control a user equipment (UE) for which a primary cell and a secondary cell are configured, the apparatus comprising: one or more processors; and one or more memories operably coupled by the one or more processors and storing instructions, wherein the one or more processors execute the instructions to: perform physical downlink control channel (PDCCH) monitoring in on-duration; receive bandwidth part (BWP) configuration information, the BWP configuration information indicating a specific BWP; receive a PDCCH based on PDCCH monitoring, the PDCCH including dormancy indication information with respect to a specific cell among a plurality of cells for the UE; transmit ACK/NACK (acknowledgement/negative-acknowledgement) information for the PDCCH including the dormancy indication information; and activate the specific BWP based on the dormancy indication information indicating non-dormancy. 